Looking for feedback on Fishman Nashville pickup

I tried the Fishman Nashville early on along with a Jerry Douglas aura and a radial PZ-Pre. It sounded better than other pickups (I think I tried them all) but I still wasn't crazy about it. Had issues with one string being louder than others. I've been using condensor mics for gigs but I'm considering trying the Fishman again. I have a few questions though. First, how does the newer pickup affect the acoustic sound of the guitar? Second, does it make a difference what type of wood the guitar is made of? I know the sampling for the Aura was done using Jerry's mahogany Beard. Has anyone installed it in a koa guitar?